The present invention relates to an evaporator, particularly one for air conditioning installations in automotive vehicles. An evaporator of this general type is known, for example, from German Offenlegungsschrift No. 31 36 374.
Because evaporators are installed under conditions of restricted space, such as in the case of air conditioning devices of automotive vehicles, the problem arises that the expansion valve cannot be placed directly in front of the manifold. The connecting line between the expansion valve and the manifold is bent in sections, often with small bending radii, as a consequence of the restricted space.
The coolant separates into a liquid and a gaseous phase as the result of the distance between the expansion valve and the manifold and particularly because of the change in direction of the coolant due to the curvature of the supply line. Consequently, a quantitatively unequal division of the total volume over the different tube lengths results, and the tubes are variously impacted. This leads to certain of the evaporator tubes overheating in relation to the others, which has a negative effect on the control behavior of the installation and the performance of the evaporator.
In order to obtain a uniform flow of the coolant prior to its division into the individual tube lengths of the evaporator, it has already been proposed in German application No. P 33 27 179.8 to place a vortex element in the coolant flow directly in front of the manifold. This vortex element bursts the two phase flow consisting of coolant vapor and coolant liquid to achieve a turbulent mixing of the two phases. The inclusion of a vortex cell of this type has lead to very good results with respect to the uniform exposure of the evaporator tubes and thus to good evaporator performance. However, in spite of its small dimensions, a vortex cell requires a certain structural space directly in front of the manifold, which is not always available. Furthermore, there is an additional expense involved in the manufacture and installation of such a vortex cell.